ME(w/o STI)-260
Cylinder Block
MECHANICAL
22.Cylinder Block
A: REMOVAL
1) Remove the engine from the vehicle. <Ref. to ME(w/o STI)-48, REMOVAL, Engine Assembly.>
2) Remove the crankshaft position sensor plate with drive plate. (CVT model) <Ref. to CVT(TR690)-137, RE-
MOVAL, Drive Plate.>
3) Remove the clutch disc and cover. (MT model) <Ref. to CL-12, REMOVAL, Clutch Disc and Cover.>
4) Remove the crankshaft position sensor plate with flywheel. (MT model) <Ref. to CL-15, REMOVAL, Fly-
wheel.>
5) Remove the intake manifold. <Ref. to FU(w/o STI)-18, REMOVAL, Intake Manifold.>
6) Remove the air intake adapter. <Ref. to FU(w/o STI)-43, REMOVAL, Tumble Generator Valve Assem-
bly.>
7) Remove the engine wiring harness. <Ref. to FU(w/o STI)-85, REMOVAL, Engine Wiring Harness.>
8) Remove the chain cover. <Ref. to ME(w/o STI)-93, REMOVAL, Chain Cover.>
9) Remove the rocker cover. <Ref. to ME(w/o STI)-152, REMOVAL, Rocker Cover.>
10) Remove the cam carrier. <Ref. to ME(w/o STI)-172, REMOVAL, Cam Carrier.>
11) Remove the cylinder head. <Ref. to ME(w/o STI)-215, REMOVAL, Cylinder Head.>
12) Remove the crank sprocket. <Ref. to ME(w/o STI)-150, REMOVAL, Crank Sprocket.>
13) Remove the engine rear hanger from cylinder block RH.
ME-06799
15WRX_STI_US_EN.book 260 ージ 20  
ME(w/o STI)-261
Cylinder Block
MECHANICAL
14) Remove the bolts securing the water pipe assembly and PCV connector to the cylinder block, and re-
move the water pipe assembly and PCV connector as a set from cylinder block.
15) Remove the O-ring from the cylinder block and PCV connector.
ME-06801
ME-06802
15WRX_STI_US_EN.book 261 ージ 20  
ME(w/o STI)-262
Cylinder Block
MECHANICAL
16) Remove the knock sensor from cylinder block LH.
17) Remove the PCV valve from the cylinder block RH.
ME-06803
ME-06804
15WRX_STI_US_EN.book 262 ージ 20  
ME(w/o STI)-263
Cylinder Block
MECHANICAL
18) Remove the bolts securing the crankshaft position sensor holder from the cylinder block LH, and remove
the crankshaft position sensor with crankshaft position sensor holder.
19) Set the part so that the oil pan is on the upper side.
20) Remove the oil pan upper with oil pan from cylinder block.
NOTE:
Pry the points shown in the figure with a crowbar wrapped by protective tape, and then remove the oil pan
upper.
(a) RH side (b) LH side
ME-06805
ME-07393
(a)
(b)
15WRX_STI_US_EN.book 263 ージ 20  
ME(w/o STI)-264
Cylinder Block
MECHANICAL
21) Remove the O-ring from the cylinder block.
22) Set the part so that the cylinder block RH is on the upper side.
ME-07394
ME-06807
15WRX_STI_US_EN.book 264 ージ 20  
ME(w/o STI)-265
Cylinder Block
MECHANICAL
23) Remove the #1 and #3 connecting rod caps and pistons from the cylinder block.
NOTE:
Mark each connecting rod cap and piston with a cylinder number.
(1) Turn the crankshaft so that the #1 connecting rod cap (A) is located at the position shown in the figure
using ST.
ST 18252AA000 CRANKSHAFT SOCKET
(2) Using ST, loosen the #1 connecting rod cap bolt, and remove the #1 connecting rod cap bolt and #1
connecting rod cap.
ST 18270AA020 SOCKET
ME-06808
ST
(A)
ME-06809
ST
15WRX_STI_US_EN.book 265 ージ 20  
ME(w/o STI)-266
Cylinder Block
MECHANICAL
(3) Using the ST, turn the crankshaft counterclockwise and separate the positions of the #1 pin (A) of
crankshaft and the large end (B) of #1 connecting rod.
ST 18252AA000 CRANKSHAFT SOCKET
(4) Push the #1 connecting rod in the direction of the arrow, and remove the #1 piston with #1 connecting
rod from the cylinder block.
ME-06877
(B)
(A)
ST
ME-06810
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ME(w/o STI)-267
Cylinder Block
MECHANICAL
(5) Turn the crankshaft so that the #3 connecting rod cap (A) is located at the position shown in the figure
using ST.
ST 18252AA000 CRANKSHAFT SOCKET
(6) Using ST, loosen the #3 connecting rod cap bolt, and remove the #3 connecting rod cap bolt and #3
connecting rod cap.
ST 18270AA020 SOCKET
ME-06811
ST
(A)
ME-06812
ST
15WRX_STI_US_EN.book 267 ージ 20  
ME(w/o STI)-268
Cylinder Block
MECHANICAL
(7) Using the ST, turn the crankshaft counterclockwise and separate the positions of the #3 pin (A) of
crankshaft and the large end (B) of #3 connecting rod.
ST 18252AA000 CRANKSHAFT SOCKET
(8) Push the #3 connecting rod in the direction of the arrow, and remove the #3 piston with #3 connecting
rod from the cylinder block.
ME-06813
ST
(B)
(A)
ME-06814
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ME(w/o STI)-269
Cylinder Block
MECHANICAL
24) Set the part so that the cylinder block LH is on the upper side.
25) Remove #2 and #4 connecting rod caps and pistons in the same removal procedure as #1 and 3# con-
necting rod caps and pistons.
26) Set the part so that the cylinder block RH is on the upper side, and separate the cylinder block.
(1) Remove the engine stand from the cylinder block RH.
ME-06815
15WRX_STI_US_EN.book 269 ージ 20  
ME(w/o STI)-270
Cylinder Block
MECHANICAL
(2) Remove the bolt shown in the figure.
(3) Loosen the cylinder block mounting bolts in numerical order as shown in the figure.
ME-06830
ME-06816
(3)
(7)
(8)
(10)
(2)
(5)
(9)
(6)
(4)
(1)
15WRX_STI_US_EN.book 270 ージ 20  
ME(w/o STI)-271
Cylinder Block
MECHANICAL
(4) While tapping the cylinder block RH with a plastic hammer, separate the cylinder block RH from the
cylinder block LH.
NOTE:
Lift the cylinder block RH gradually, and confirm that the crankshaft is remaining in the cylinder block LH. If the cyl-
inder block RH is lifted carelessly when separating, the crankshaft may stick to cylinder block RH, then fall off.
27) Remove the crankshaft from cylinder block LH, and remove the rear oil seal.
28) Remove the O-ring from the cylinder block LH.
29) Remove the crankshaft bearings from the cylinder block.
NOTE:
Be careful not to confuse the crankshaft bearing combination.
Press the bearing at the end opposite to locking lip (A).
ME-06817
ME-06818
(A)
(
A)
(A)
(A)
LH
RH
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ME(w/o STI)-272
Cylinder Block
MECHANICAL
30) Remove the liquid gasket from cylinder block.
31) Remove the cylinder block LH from the engine stand.
B: INSTALLATION
1) Install the cylinder block LH to the engine stand.
2) Apply engine oil to the crankshaft bearing, and install the crankshaft bearing to the cylinder block.
CAUTION:
When performing the operation of the cylinder block RH, be careful of the following.
1. Place a wood board wrapped with a waste cloth to prevent the knock pin damage and to stabilize
the cylinder block before work.
2. Be careful not to scratch the mating surface of cylinder block during work.
ME-06819
LH
RH
15WRX_STI_US_EN.book 272 ージ 20  
ME(w/o STI)-273
Cylinder Block
MECHANICAL
3) Install O-rings to the cylinder block LH.
NOTE:
Use new O-rings.
ME-06817
15WRX_STI_US_EN.book 273 ージ 20  
ME(w/o STI)-274
Cylinder Block
MECHANICAL
4) Apply engine oil to the crankshaft journal, and set the crankshaft to cylinder block LH.
5) Apply liquid gasket to the mating surface of cylinder block RH as shown in the figure.
CAUTION:
Place a wood board wrapped with a waste cloth to prevent the knock pin damage and to stabilize
the cylinder block before work.
Be careful not to scratch the mating surface of cylinder block during work.
Do not let the liquid gasket overflow to the oil passage and crankshaft bearing portions, because
the engine seizure may result.
ME-06820
15WRX_STI_US_EN.book 274 ージ 20  
ME(w/o STI)-275
Cylinder Block
MECHANICAL
NOTE:
Before applying liquid gasket, degrease the old liquid gasket seal surface of the cylinder block RH and cyl-
inder block LH.
Install within 5 min. after applying liquid gasket.
Liquid gasket:
THREE BOND 1217G (Part No. K0877Y0100) or equivalent
Liquid gasket applying diameter:
Mating surfaces other than ranges A, B and C
1
±
0.5 mm (0.0394
±
0.0197 in)
Mating surfaces of ranges A and C
4
±
0.5 mm (0.1575
±
0.0197 in)
Mating surfaces of range B
3.2
±
0.5 mm (0.1260
±
0.0197 in)
6) Install the cylinder block RH to the cylinder block LH.
(A) Range A (F) Liquid gasket applying position of
mating surfaces (the edge) of
range C
(K) 2 mm (0.0787 in)
(B) Range B (G) 1 mm (0.0394 in) or less (L) 36 mm (1.4173 in)
(C) Range C (H) φ3.2±0.5 mm (0.1260±0.0197 in) (M) 2.5 mm (0.0984 in)
(D) Liquid gasket applying position of
mating surfaces of range B
(I) Chamfer edge
(E) Liquid gasket applying position of
mating surfaces (other than the
edge) of range C
(J) φ4±0.5 mm (0.1575±0.0197 in)
ME-06821
B-B
(E)
(G)
(J)
(I)
(I)
(K)
(J)
C-C
(F)
(L)
(M)
(I)
(I)
C
C
B
B
A
A
:(A)
:(B)
:(C)
A-A
(D)
(G)
(H)
(I)
15WRX_STI_US_EN.book 275 ージ 20  
ME(w/o STI)-276
Cylinder Block
MECHANICAL
7) Join the cylinder blocks.
(1) Apply a coat of engine oil to the washers and cylinder block mounting bolt threads.
NOTE:
To prevent mixture of engine oil into the water jacket, do not apply a large amount.
(2) Tighten all mounting bolts with a torque of 35 N·m (3.6 kgf-m, 25.8 ft-lb) in numerical order as shown
in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06822
(8)
(4)
(3)
(9)
(6)
(2)
(5)
(7)
(1)
(10)
15WRX_STI_US_EN.book 276 ージ 20  
ME(w/o STI)-277
Cylinder Block
MECHANICAL
(3) Loosen all mounting bolts by 180° in numerical order as shown in the figure.
CAUTION:
When loosening the mounting bolts, hold the cylinder block LH while not holding the cylinder block
RH to ensure the joint accuracy of the cylinder block.
ME-06816
(3)
(7)
(8)
(10)
(2)
(5)
(9)
(6)
(4)
(1)
15WRX_STI_US_EN.book 277 ージ 20  
ME(w/o STI)-278
Cylinder Block
MECHANICAL
(4) Tighten all mounting bolts with a torque of 35 N·m (3.6 kgf-m, 25.8 ft-lb) in numerical order as shown
in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06822
(8)
(4)
(3)
(9)
(6)
(2)
(5)
(7)
(1)
(10)
15WRX_STI_US_EN.book 278 ージ 20  
ME(w/o STI)-279
Cylinder Block
MECHANICAL
(5) Loosen the mounting bolts (4 places) by 180° in numerical order as shown in the figure.
CAUTION:
When loosening the mounting bolts, hold the cylinder block LH while not holding the cylinder block
RH to ensure the joint accuracy of the cylinder block.
ME-06824
(3)
(4)
(1)
(2)
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ME(w/o STI)-280
Cylinder Block
MECHANICAL
(6) Tighten the mounting bolts (4 places) with a torque of 17 N·m (1.7 kgf-m, 12.5 ft-lb) in numerical order
as shown in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06825
(2)
(1)
(4)
(3)
15WRX_STI_US_EN.book 280 ージ 20  
ME(w/o STI)-281
Cylinder Block
MECHANICAL
(7) Using angle gauge, tighten the mounting bolts (4 places) with specified angle in numerical order as
shown in the figure.
CAUTION:
When tightening the mounting bolts with specified angle, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
Tightening angle:
60°
±
ME-07266
(1)
(2)
(4)
(3)
15WRX_STI_US_EN.book 281 ージ 20  
ME(w/o STI)-282
Cylinder Block
MECHANICAL
(8) Loosen the mounting bolts (6 places) by 180° in numerical order as shown in the figure.
CAUTION:
When loosening the mounting bolts, hold the cylinder block LH while not holding the cylinder block
RH to ensure the joint accuracy of the cylinder block.
ME-06827
(1)
(4)
(5)
(2)
(3)
(6)
15WRX_STI_US_EN.book 282 ージ 20  
ME(w/o STI)-283
Cylinder Block
MECHANICAL
(9) Tighten the mounting bolts (6 places) with a torque of 17 N·m (1.7 kgf-m, 12.5 ft-lb) in numerical order
as shown in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06828
(6)
(3)
(2)
(5)
(4)
(1)
15WRX_STI_US_EN.book 283 ージ 20  
ME(w/o STI)-284
Cylinder Block
MECHANICAL
(10) Using angle gauge, tighten the mounting bolts (6 places) with specified angle in numerical order as
shown in the figure.
CAUTION:
When tightening the mounting bolts with specified angle, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
Tightening angle:
60°
±
ME-07267
(1)
(4)
(6)
(5)
(2)
(3)
15WRX_STI_US_EN.book 284 ージ 20  
ME(w/o STI)-285
Cylinder Block
MECHANICAL
(11) Install the bolt shown in the figure.
NOTE:
After tightening, if the liquid gasket is squeezed out in the seal surface area of the chain cover and oil pan up-
per, completely remove any liquid gasket that is squeezed out. Any liquid gasket on the chamfer area, how-
ever, should not be removed.
Tightening torque:
25 N·m (2.5 kgf-m, 18.4 ft-lb)
8) Set the part so that the installation surface of the oil pan upper is on the upper side.
9) Check that the piston ring gap for each piston is positioned correctly. <Ref. to ME(w/o STI)-309, PISTON
AND CONNECTING ROD, ASSEMBLY, Cylinder Block.>
ME-06830
15WRX_STI_US_EN.book 285 ージ 20  
ME(w/o STI)-286
Cylinder Block
MECHANICAL
10) Install the piston and connecting rod to the cylinder block.
(1) Apply engine oil to the outer circumference of each piston, crankshaft pin, and in the cylinder block.
(2) Turn the crankshaft so that the #1 pin (A) of crankshaft is positioned at TDC using ST.
ST 18252AA000 CRANKSHAFT SOCKET
ME-06831
ST
(A)
15WRX_STI_US_EN.book 286 ージ 20  
ME(w/o STI)-287
Cylinder Block
MECHANICAL
(3) Compress the piston ring using piston ring compressor, and insert the #1 connecting rod with #1 pis-
ton into cylinder block.
CAUTION:
Be careful not to damage the cylinder liner and #1 pin of crankshaft by the #1 connecting rod large
end.
Be careful not to apply strong impact when inserting to prevent connecting rod bearing from fall-
ing off.
NOTE:
Face the piston front mark (round mark) towards the front of the engine.
Insert while lightly tapping the crown of the piston with the handle of a plastic hammer.
(a) Front mark
ME-07021
(a)
ME-06832
15WRX_STI_US_EN.book 287 ージ 20  
ME(w/o STI)-288
Cylinder Block
MECHANICAL
(4) Turn the crankshaft counterclockwise so that the #1 pin of crankshaft and the large end (A) of #1 con-
necting rod are positioned as shown in the figure using ST, while pressing the #1 piston crown, and then
set the #1 connecting rod cap and #1 connecting rod cap bolt.
NOTE:
Each connecting rod has its own mating cap. Make sure that they are assembled correctly by checking
their matching symbol.
Use a new connecting rod cap bolt.
Apply a coat of engine oil to the #1 connecting rod cap seat and the connecting rod cap bolt threads.
ST 18252AA000 CRANKSHAFT SOCKET
ME-06833
ST
(A)
15WRX_STI_US_EN.book 288 ージ 20  
ME(w/o STI)-289
Cylinder Block
MECHANICAL
(5) Using ST, tighten the #1 connecting rod cap bolts to 10 N·m (1.0 kgf-m, 7.4 ft-lb) in numerical order
as shown in the figure, then retighten the bolts to 25 N·m (2.5 kgf-m, 18.4 ft-lb) in numerical order as
shown in the figure.
ST 18270AA020 SOCKET
(6) Turn the crankshaft clockwise so that the #2 pin (A) of crankshaft is positioned at TDC using ST.
ST 18252AA000 CRANKSHAFT SOCKET
ME-06834
ST
(2)
(1)
ME-06835
ST
(A)
15WRX_STI_US_EN.book 289 ージ 20  
ME(w/o STI)-290
Cylinder Block
MECHANICAL
(7) Compress the piston ring using piston ring compressor, and insert the #2 connecting rod with #2 pis-
ton into cylinder block.
CAUTION:
Be careful not to damage the cylinder liner and #2 pin of crankshaft by the #2 connecting rod large
end.
Be careful not to apply strong impact when inserting to prevent connecting rod bearing from fall-
ing off.
NOTE:
Face the piston front mark (round mark) towards the front of the engine.
Insert while lightly tapping the crown of the piston with the handle of a plastic hammer.
(a) Front mark
ME-07022
(a)
ME-06836
15WRX_STI_US_EN.book 290 ージ 20  
ME(w/o STI)-291
Cylinder Block
MECHANICAL
(8) Turn the crankshaft clockwise so that the #2 pin of crankshaft and the large end (A) of #2 connecting
rod are positioned as shown in the figure using ST, while pressing the #2 piston crown, and then set the
#2 connecting rod cap and #2 connecting rod cap bolt.
NOTE:
Each connecting rod has its own mating cap. Make sure that they are assembled correctly by checking
their matching symbol.
Use a new connecting rod cap bolt.
Apply a coat of engine oil to the #2 connecting rod cap seat and the connecting rod cap bolt threads.
ST 18252AA000 CRANKSHAFT SOCKET
ME-06837
ST
(A)
15WRX_STI_US_EN.book 291 ージ 20  
ME(w/o STI)-292
Cylinder Block
MECHANICAL
(9) Using ST, tighten the #2 connecting rod cap bolts to 10 N·m (1.0 kgf-m, 7.4 ft-lb) in numerical order
as shown in the figure, then retighten the bolts to 25 N·m (2.5 kgf-m, 18.4 ft-lb) in numerical order as
shown in the figure.
ST 18270AA020 SOCKET
(10) Install #3 and #4 pistons and connecting rod caps in the same installation procedure as #1 and #2
pistons and connecting rod caps.
(11) Using ST and angle gauge, tighten the #1 connecting rod cap bolts and #4 connecting rod cap bolts
with specified angle in numerical order as shown in the figure.
ST 18270AA020 SOCKET
Tightening angle:
90°
+5°
–0°
ME-06838
ST
(2)
(1)
ME-07268
ST
(2)
(1)
ST
(2)
(1)
15WRX_STI_US_EN.book 292 ージ 20  
ME(w/o STI)-293
Cylinder Block
MECHANICAL
(12) Turn the crankshaft so that the #2 connecting rod cap (A) and #3 connecting rod cap (B) is located
at the position shown in the figure using ST.
ST 18252AA000 CRANKSHAFT SOCKET
(13) Using ST and angle gauge, tighten the #2 connecting rod cap bolts and #3 connecting rod cap bolts
with specified angle in numerical order as shown in the figure.
ST 18270AA020 SOCKET
Tightening angle:
90°
+5°
–0°
ME-06840
ST
(A)
(B)
ME-07269
ST
(2)
(1)
ST
(2)
(1)
15WRX_STI_US_EN.book 293 ージ 20  
ME(w/o STI)-294
Cylinder Block
MECHANICAL
11) Install the oil pan upper with oil pan to the cylinder block.
(1) Apply liquid gasket to the mating surface of oil pan upper as shown in the figure.
NOTE:
Before applying liquid gasket, degrease the old liquid gasket seal surface of the cylinder block and the oil
pan upper.
Install within 5 min. after applying liquid gasket.
Apply liquid gasket 1.5 mm (0.0591 in) outside from the chamfer surface. However, application of liquid
gasket on the chamfer surface around the bolt hole is allowed.
Liquid gasket:
THREE BOND 1217G (Part No. 0877Y0100) or equivalent
Liquid gasket applying diameter:
5
±
1 mm (0.1969
±
0.0394 in)
(A) Chamfer surface (B) 1.5 mm (0.0591 in)
ME-07395
(B)
(B)
:(A)
15WRX_STI_US_EN.book 294 ージ 20  
ME(w/o STI)-295
Cylinder Block
MECHANICAL
(2) Install the O-ring to the cylinder block.
NOTE:
Use new O-rings.
ME-06807
15WRX_STI_US_EN.book 295 ージ 20  
ME(w/o STI)-296
Cylinder Block
MECHANICAL
(3) Set the oil pan with oil pan upper to the cylinder block, and tighten the bolts in numerical order as
shown in the figure.
NOTE:
After tightening, if the liquid gasket is squeezed out onto the seal surface of the chain cover, completely re-
move any squeezed-out liquid gasket.
Tightening torque:
18 N·m (1.8 kgf-m, 13.3 ft-lb)
12) Set the part so that the installation surface of the intake manifold is on the upper side.
(A) M8 × 25 (B) M8 × 75
ME-07396
(A)
(12)
(8)
(10)
(6)
(3)
(1)
(5)
(7)
(9)
(4)
(2)
(13)
(11)
(B)
15WRX_STI_US_EN.book 296 ージ 20  
ME(w/o STI)-297
Cylinder Block
MECHANICAL
13) Install the crankshaft position sensor with crankshaft position sensor holder to the cylinder block LH.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
14) Install the PCV valve onto the cylinder block RH.
NOTE:
Apply liquid gasket to the bolt threads of PCV valve.
Liquid gasket:
THREE BOND 1324 (Part No. 004403042) or equivalent
Tightening torque:
23 N·m (2.3 kgf-m, 17.0 ft-lb)
ME-06805
ME-06804
15WRX_STI_US_EN.book 297 ージ 20  
ME(w/o STI)-298
Cylinder Block
MECHANICAL
15) Install the knock sensor to the cylinder block LH.
NOTE:
Knock sensor must be positioned toward engine front so that the connector center position is within the range
of shaded area shown in the figure.
Tightening torque:
24 N·m (2.4 kgf-m, 17.7 ft-lb)
(A) Front of engine
ME-06844
(A)
(A)
15WRX_STI_US_EN.book 298 ージ 20  
ME(w/o STI)-299
Cylinder Block
MECHANICAL
16) Install the O-ring to the cylinder block and PCV connector.
NOTE:
Use new O-rings.
17) Install the water pipe assembly and PCV connector to the cylinder block.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
ME-06802
ME-06801
15WRX_STI_US_EN.book 299 ージ 20  
ME(w/o STI)-300
Cylinder Block
MECHANICAL
18) Install the engine rear hanger to the cylinder block RH.
Tightening torque:
21 N·m (2.1 kgf-m, 15.5 ft-lb)
19) Install the crank sprocket. <Ref. to ME(w/o STI)-150, INSTALLATION, Crank Sprocket.>
20) Install the cylinder head. <Ref. to ME(w/o STI)-218, INSTALLATION, Cylinder Head.>
21) Install the cam carrier. <Ref. to ME(w/o STI)-180, INSTALLATION, Cam Carrier.>
22) Install the rocker cover. <Ref. to ME(w/o STI)-161, INSTALLATION, Rocker Cover.>
23) Install the chain cover. <Ref. to ME(w/o STI)-101, INSTALLATION, Chain Cover.>
24) Install the engine wiring harness. <Ref. to FU(w/o STI)-88, INSTALLATION, Engine Wiring Harness.>
25) Install the air intake adapter. <Ref. to FU(w/o STI)-44, INSTALLATION, Tumble Generator Valve Assem-
bly.>
26) Install the intake manifold. <Ref. to FU(w/o STI)-29, INSTALLATION, Intake Manifold.>
ME-06799
15WRX_STI_US_EN.book 300 ージ 20  
ME(w/o STI)-301
Cylinder Block
MECHANICAL
27) Apply a coat of engine oil to the oil seal inner periphery and outer periphery, and install the rear oil seal
using ST1 and ST2.
NOTE:
Use a new rear oil seal.
ST1 18671AA020 OIL SEAL GUIDE
ST2 18657AA030 OIL SEAL INSTALLER
28) Install the crankshaft position sensor plate with drive plate. (CVT model) <Ref. to CVT(TR690)-138, IN-
STALLATION, Drive Plate.>
29) Install the crankshaft position sensor plate with flywheel. (MT model) <Ref. to CL-15, INSTALLATION,
Flywheel.>
30) Install the clutch disc and cover. (MT model) <Ref. to CL-12, INSTALLATION, Clutch Disc and Cover.>
31) Install the engine to the vehicle. <Ref. to ME(w/o STI)-61, INSTALLATION, Engine Assembly.>
(A) Rear oil seal (B) Drive plate or flywheel mounting
bolt
ME-06878
ST2
(B)
ST1
(A)
15WRX_STI_US_EN.book 301 ージ 20  
ME(w/o STI)-302
Cylinder Block
MECHANICAL
C: DISASSEMBLY
1. CYLINDER BLOCK
1) Remove the oil separator cover from cylinder block RH.
2) Remove the liquid gasket from cylinder block RH.
3) Remove the cylinder block plug (A) and the main gallery plug (B) from cylinder block RH.
4) Remove the liquid gasket from the thread holes of the cylinder block RH, and from the threaded portions
of cylinder block plug and main gallery plug.
ME-06846
ME-06847
(A)
(B)
15WRX_STI_US_EN.book 302 ージ 20  
ME(w/o STI)-303
Cylinder Block
MECHANICAL
5) Remove the cylinder block plate from cylinder block LH.
6) Remove the main gallery plug from cylinder block LH.
7) Remove the liquid gasket from the thread holes of the cylinder block LH and main gallery plug.
ME-07991
ME-06849
15WRX_STI_US_EN.book 303 ージ 20  
ME(w/o STI)-304
Cylinder Block
MECHANICAL
2. PISTON AND CONNECTING ROD
NOTE:
To prevent confusion of various parts, mark each part.
1) Remove the connecting rod bearing from connecting rod and connecting rod cap.
2) Remove the piston rings from the piston.
NOTE:
Arrange the piston rings in order so that they can be installed in their original positions without confusion.
(1) Remove the compression rings in the order of top ring and second ring, using piston ring expander.
(2) Remove the oil rings in the order of upper rail, lower rail and expander by hand.
3) Remove the circlip on one end from the piston using a flat tip screwdriver.
NOTE:
Be careful not damage the piston and piston pin, by wrapping the tip of flat tip screwdriver with tape.
4) Remove the piston pin from piston, and remove the connecting rod from piston.
5) Remove the circlip on other end from the piston using a flat tip screwdriver.
NOTE:
Be careful not damage the piston and piston pin, by wrapping the tip of flat tip screwdriver with tape.
(1) Connecting rod (4) Piston (7) Oil ring
(2) Connecting rod bearing (5) Piston pin (8) Second ring
(3) Connecting rod cap (6) Circlip (9) Top ring
(1)
(5)
(6)
(9)
(8)
(7)
(4)
(6)
ME-06850
(3)
(2)
(2)
15WRX_STI_US_EN.book 304 ージ 20  
ME(w/o STI)-305
Cylinder Block
MECHANICAL
D: ASSEMBLY
1. CYLINDER BLOCK
1) Apply liquid gasket to the threaded portion of the main gallery plug, and install the main gallery plug to the
cylinder block LH.
NOTE:
Before applying liquid gasket, degrease the thread holes of the cylinder block LH and main gallery plug.
Liquid gasket:
THREE BOND 1105 (Part No. 004403010) or equivalent
Tightening torque:
37 N·m (3.8 kgf-m, 27.3 ft-lb)
ME-06851
15WRX_STI_US_EN.book 305 ージ 20  
ME(w/o STI)-306
Cylinder Block
MECHANICAL
2) Install the cylinder block plate onto cylinder block LH.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
ME-07991
15WRX_STI_US_EN.book 306 ージ 20  
ME(w/o STI)-307
Cylinder Block
MECHANICAL
3) Apply liquid gasket to the threaded portions of cylinder block plug and main gallery plug, and install the cyl-
inder block plug (A) and main gallery plug (B) to cylinder block RH.
NOTE:
Before applying liquid gasket, degrease the thread holes of the cylinder block RH, and the threaded portions
of cylinder block plug and main gallery plug.
Liquid gasket:
THREE BOND 1105 (Part No. 004403010) or equivalent
Tightening torque:
T1: 16 N·m (1.6 kgf-m, 11.8 ft-lb)
T2: 37 N·m (3.8 kgf-m, 27.3 ft-lb)
ME-06852
(A)
(B)
T1
T2
15WRX_STI_US_EN.book 307 ージ 20  
ME(w/o STI)-308
Cylinder Block
MECHANICAL
4) Install the oil separator cover to the cylinder block RH.
(1) Apply liquid gasket to the mating surfaces of oil separator cover.
NOTE:
Use new oil separator cover.
Before applying liquid gasket, degrease the old liquid gasket seal surface of cylinder block RH.
Install within 5 min. after applying liquid gasket.
Liquid gasket:
Mating surface
THREE BOND 1217G (Part No. K0877Y0100) or equivalent
Liquid gasket applying diameter:
4
±
1 mm (0.1772
±
0.0394 in)
(2) Install the oil separator cover to the cylinder block RH, and tighten the oil separator cover bolts in nu-
merical order as shown in the figure.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
ME-06853
ME-06854
(4)
(5)
(7)
(6)
(1)
(3)
(2)
15WRX_STI_US_EN.book 308 ージ 20  
ME(w/o STI)-309
Cylinder Block
MECHANICAL
2. PISTON AND CONNECTING ROD
1) Install the connecting rod bearing to the connecting rod and connecting rod cap.
2) Install the circlip on one end of the piston using a flat tip screwdriver.
NOTE:
Be careful not damage the piston, by wrapping the tip of flat tip screwdriver with tape.
Make sure the circlip is firmly inserted into the circlip groove.
After installing the circlip, rotate the circlip so that its end part (a) and the cutout portion of circlip groove (b)
do not match.
(1) Connecting rod (4) Piston (7) Oil ring
(2) Connecting rod bearing (5) Piston pin (8) Second ring
(3) Connecting rod cap (6) Circlip (9) Top ring
(1)
(5)
(6)
(9)
(8)
(7)
(4)
(6)
ME-06855
(3)
(2)
(2)
ME-06823
(a)
(b)
(b)
(a)
15WRX_STI_US_EN.book 309 ージ 20  
ME(w/o STI)-310
Cylinder Block
MECHANICAL
3) Set the piston to the connecting rod.
NOTE:
Align the front mark of piston and the connecting rod direction correctly as shown in the figure.
4) Apply engine oil to the piston pin, and attach the piston pin.
(a) RH side (#1 and #3) (b) LH side (#2 and #4) (c) Front mark
ME-08024
(a)
(b)
(c)
(c)
15WRX_STI_US_EN.book 310 ージ 20  
ME(w/o STI)-311
Cylinder Block
MECHANICAL
5) Install the circlip on the piston using a flat tip screwdriver.
NOTE:
Be careful not damage the piston and piston pin, by wrapping the tip of flat tip screwdriver with tape.
Make sure the circlip is firmly inserted into the circlip groove.
After installing the circlip, rotate the circlip so that its end part (a) and the cutout portion of circlip groove (b)
do not match.
6) Install the oil rings to the piston in the order of expander, lower rail and upper rail by hand.
NOTE:
Oil ring consists of the upper rail, expander and lower rail.
(a) Upper rail (b) Expander (c) Lower rail
ME-06859
(a)
(
a
)
(
b
)
(b
)
ME-06860
(a)
(b)
(c)
(a)
(b)
(c)
15WRX_STI_US_EN.book 311 ージ 20  
ME(w/o STI)-312
Cylinder Block
MECHANICAL
(1) Set the ring gap of the expander to the position (A).
ME-06861
RH
LH
(A)
(A)
15WRX_STI_US_EN.book 312 ージ 20  
ME(w/o STI)-313
Cylinder Block
MECHANICAL
(2) Set the lower rail spin stopper (D) to the oil groove (C) located above the cutout portion (B) of the pis-
ton skirt coating, and hook the lower rail spin stopper (F) to the expander (E).
ME-07477
RH
LH
(C)
(C)
(C)
(D)
(E)
(C)
(F)
(B)
(B)
15WRX_STI_US_EN.book 313 ージ 20  
ME(w/o STI)-314
Cylinder Block
MECHANICAL
(3) Set the upper rail gap to the position (G), and hook the upper rail spin stopper (H) to the expander (E).
7) Install the compression rings to the piston in the order of second ring and top ring, using piston ring ex-
pander.
(1) Set the ring gap of the second ring to the position (A) in the figure.
NOTE:
Install the second ring so that the ring mark (2N) faces the piston crown.
ME-07518
RH
LH
(G)
0 20
(G)
0 20
(E)
(H)
(E)
(H)
ME-07140
RH
LH
(A)
(A)
15WRX_STI_US_EN.book 314 ージ 20  
ME(w/o STI)-315
Cylinder Block
MECHANICAL
(2) Set the ring gap of top ring at (B) in the figure on the 180° opposite direction of (A).
NOTE:
Install the top ring so that the ring mark (TN) faces the piston crown.
8) Check that the piston ring is installed correctly.
ME-07141
RH
LH
180
(A)
(B)
(B)
(A)
180
15WRX_STI_US_EN.book 315 ージ 20  
ME(w/o STI)-316
Cylinder Block
MECHANICAL
E: INSPECTION
1. CYLINDER BLOCK & PISTON
1) Visually inspect to make sure that there are no cracks, scratches or other damage.
2) Use liquid penetrant tester on the important sections to check for fissures.
3) Check that there are no traces of gas leaking or water leaking on the gasket attachment surface.
4) Check the oil passages for clogging.
5) Check for warpage of mating surfaces of the cylinder block that contacts cylinder head using a straight
edge and thickness gauge. If it exceeds the limit, correct the surface by grinding it with a surface grinder or
replace the cylinder block.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Cylinder block warpage:
Limit
0.025 mm (0.00098 in)
Grinding limit of cylinder block :
To 204.9 mm (8.067 in)
Height of cylinder block:
Standard
205.0 mm (8.071 in)
6) Using a cylinder bore gauge, check the cylindricality and out-of-roundness of cylinder liner. If it is not within
the standard, perform reboring (including honing), or replace the cylinder block and piston as a set. For re-
boring and honing procedure, refer to step 8).
NOTE:
Measure the cylinder liner with cylinder blocks separated (into cylinder block RH and cylinder block LH).
Measurement should be performed at a temperature of 20°C (68°F).
Write down all measurement values as the values are used in the next procedure.
Measure the inner diameter of each cylinder liner in both the thrust and piston pin directions at the heights
as shown in the figure.
(A) Piston pin direction (B) Thrust direction
H1: 10 mm (0.3937 in) H2: 45 mm (1.7717 in) H3: 80 mm (3.1496 in)
H4: 105 mm (4.1339 in)
ME-06865
H1
H2
H3
H4
(A)
(B)
15WRX_STI_US_EN.book 316 ージ 20  
ME(w/o STI)-317
Cylinder Block
MECHANICAL
Calculate the cylindricality of cylinder liner by using the following formula.
Calculate the out-of-roundness of cylinder liner at each measurement height by using the following formu-
la.
Cylindricality of cylinder liner:
Limit
0.030 mm (0.0012 in)
Out-of-roundness of cylinder liner:
Limit
0.030 mm (0.0012 in)
7) Check the clearance between cylinder liner and piston. Check the clearance between cylinder liner and
piston by measuring the inner diameter of cylinder liner and the outer diameter of piston respectively.
(1) Measure the inner diameter of cylinder liner. If it is not within the standard, perform reboring (including
honing), or replace the cylinder block and piston as a set. For reboring and honing procedure, refer to step
8).
NOTE:
Measure the cylinder liner with cylinder blocks separated (into cylinder block RH and cylinder block LH).
Measurement should be performed at a temperature of 20°C (68°F).
The cylinder bore size mark is stamped on the upper face of the cylinder block.
Calculation formula
C = (D(a)–D(b))/2
C: Cylindricality of cylinder liner
D(a): The largest value of all the measurement values for cylinder liner inner diameter
D(b): The smallest value of all the measurement values for cylinder liner inner diameter
Calculation formula
R = (D(c)–D(d))/2
R: Out-of-roundness of cylinder liner
D(c): The larger value between the measurement values in the piston pin direction and in the thrust direction of cylinder liner inner
diameter
D(d): The smaller value between the measurement values in the piston pin direction and in the thrust direction of cylinder liner
inner diameter
(A) Main journal size mark (C) #1 cylinder bore size mark (E) #3 cylinder bore size mark
(B) Cylinder block (RH) – (LH) combi-
nation mark
(D) #2 cylinder bore size mark (F) #4 cylinder bore size mark
ME-07992
(D)
(F)
(B)
(A)
(C)
(E)
#1
#2
#3
#4
#5
15WRX_STI_US_EN.book 317 ージ 20  
ME(w/o STI)-318
Cylinder Block
MECHANICAL
Measure the inner diameter of each cylinder liner in both the thrust and piston pin directions at the heights
as shown in the figure and read the value of the most worn location.
Inner diameter of cylinder liner:
Cylinder bore size mark A
Standard
86.005 — 86.015 mm (3.3860 — 3.3864 in)
Cylinder bore size mark B
Standard
85.995 — 86.005 mm (3.3856 — 3.3860 in)
(A) Piston pin direction (B) Thrust direction
H1: 10 mm (0.3937 in) H2: 45 mm (1.7717 in) H3: 80 mm (3.1496 in)
H4: 105 mm (4.1339 in)
ME-06865
H1
H2
H3
H4
(A)
(B)
15WRX_STI_US_EN.book 318 ージ 20  
ME(w/o STI)-319
Cylinder Block
MECHANICAL
(2) Check the outer diameter of piston with a micrometer. If it is not within the standard, replace the piston.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Measure the outer diameter of each piston in thrust direction at the height as shown in the figure.
Standard sized pistons are classified into two grades, “A” and “B”. These grades should be used as guide
lines in selecting a standard piston.
The grade can be judged by the stamp of cylinder bore size mark on the upper face of the cylinder block.
(A) Main journal size mark (C) #1 cylinder bore size mark (E) #3 cylinder bore size mark
(B) Cylinder block (RH) – (LH) combi-
nation mark
(D) #2 cylinder bore size mark (F) #4 cylinder bore size mark
ME-07992
(D)
(F)
(B)
(A)
(C)
(E)
#1
#2
#3
#4
#5
15WRX_STI_US_EN.book 319 ージ 20  
ME(w/o STI)-320
Cylinder Block
MECHANICAL
If the piston is replaced, check the clearance between cylinder liner and piston in the step (3), and select
a suitable sized piston.
Piston grade point H:
40.0 mm (1.57 in)
Piston outer diameter:
Standard size (grade A = cylinder bore size mark A)
Standard
85.985 — 85.995 mm (3.3852 — 3.3856 in)
Standard size (grade B = cylinder bore size mark B)
Standard
85.975 — 85.985 mm (3.3848 — 3.3852 in)
(3) Calculate the clearance between cylinder liner and piston. If it is not within the standard, perform re-
boring (including honing), or replace the cylinder block and piston as a set. For reboring and honing pro-
cedure, refer to step 8).
NOTE:
The clearance between cylinder liner and piston is decided by matching the cylinder block bore size mark
and the grade of piston outer diameter (grade A or B).
Clearance between cylinder liner and piston:
Standard
0.010 — 0.030 mm (0.00039 — 0.00118 in)
ME-06866
H
15WRX_STI_US_EN.book 320 ージ 20  
ME(w/o STI)-321
Cylinder Block
MECHANICAL
8) Reboring and honing
(1) If any of the cylindricality, out-of-roundness, inner diameter or clearance between cylinder liner and
piston is out of standard or if there is any damage on the cylinder liner, perform reboring (including hon-
ing).
CAUTION:
When any of the cylinder liner needs reboring, all other cylinder liners must be rebored at the same
time, and replaced with proper size pistons.
Oversize piston outer diameter:
0.25 mm (0.0098 in) oversize
Standard
86.225 — 86.245 mm (3.3947 — 3.3955 in)
0.50 mm (0.0197 in) oversize
Standard
86.475 — 86.495 mm (3.4045 — 3.4053 in)
(2) If the inner diameter of cylinder liner exceeds the limit after reboring (including honing), replace the
cylinder block and piston as a set.
NOTE:
Immediately after reboring (including honing), the inner diameter of cylinder liner may differ from its real di-
ameter due to temperature rise. Thus, when measuring the inner diameter of cylinder liner, wait until the tem-
perature has cooled to 20°C (68°F).
For the measurement of the inner diameter of cylinder liner, refer to step 7).
Inner diameter of cylinder liner boring limit (diameter):
To 86.505 mm (3.4057 in)
2. PISTON AND PISTON PIN
1) Check the piston and piston pin for wear or crack.
2) Check the snap ring for distortion or wear.
3) Check the piston ring groove for damage.
4) Check the circlip groove (A) for burr.
NOTE:
If the burr is found, remove the burr from groove.
5) Check that the piston pin can be inserted into the piston with a thumb at 20°C (68°F).
ME-06867
(A)
15WRX_STI_US_EN.book 321 ージ 20  
ME(w/o STI)-322
Cylinder Block
MECHANICAL
6) Check the clearance between piston and piston pin. Check the clearance between piston and piston pin
by measuring the inner diameter of piston pin hole and the outer diameter of piston pin respectively.
(1) Using a caliper gauge, measure the inner diameter of piston pin hole.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Measure the inner diameter of the piston pin hole at the four locations as shown in the figure, and read the
value of most worn location.
Record the measured value.
(2) Measure the outer diameter of piston pin with a micrometer.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Measure the outer diameter of the piston pin at the four locations as shown in the figure, and read the value
of most worn location.
Record the measured value.
(A) 10 mm (0.394 in)
ME-08025
ME-06105
(A)
(A)
15WRX_STI_US_EN.book 322 ージ 20  
ME(w/o STI)-323
Cylinder Block
MECHANICAL
(3) Calculate the clearance between piston and piston pin. If it is not within the standard, replace the pis-
ton and piston pin as a set.
Clearance between piston and piston pin:
Standard
0.004 — 0.008 mm (0.0002 — 0.0003 in)
3. PISTON RING
1) Make sure the piston ring is not broken or damaged.
2) Using a cylindrical guide, insert the piston ring into the cylinder liner so that they are perpendicular to the
cylinder wall, and check the piston ring gap using a thickness gauge. If it is not within the standard, replace
the piston ring.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Use piston ring with same size as piston when replacing piston ring.
Piston ring gap:
Compression ring (top ring)
Standard
0.20 — 0.25 mm (0.0079 — 0.0098 in)
Compression ring (second ring)
Standard
0.40 — 0.50 mm (0.0157 — 0.0197 in)
Oil ring (upper rail and lower rail)
Standard
0.10 — 0.35 mm (0.0039 — 0.0138 in)
ME-06869
15WRX_STI_US_EN.book 323 ージ 20  
ME(w/o STI)-324
Cylinder Block
MECHANICAL
3) Fit the compression ring straight into the piston ring groove, then check the clearance between compres-
sion ring and piston with a thickness gauge. If it is not within the standard, replace the compression ring.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Before inspecting the clearance, clean the piston ring groove and compression ring.
Use compression ring with same size as piston when replacing compression ring.
Clearance between compression ring and piston:
Top ring
Standard
0.040 — 0.080 mm (0.0016 — 0.0031 in)
Second ring
Standard
0.045 — 0.085 mm (0.0018 — 0.0033 in)
ME-05372
15WRX_STI_US_EN.book 324 ージ 20  
ME(w/o STI)-325
Cylinder Block
MECHANICAL
4. CONNECTING ROD AND CONNECTING ROD BEARING
1) Check for bend or twist using a connecting rod aligner. If it exceeds the limit, replace the connecting rod.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Bend or twist per 100 mm (3.94 in) in length:
Limit
0.10 mm (0.0039 in)
2) Check that the large or small end thrust surface of each connecting rod is not damaged.
3) Check each connecting rod bearing for scar, peeling, seizure, melting or wear, etc.
4) Check the thrust clearance of each connecting rod using a thickness gauge.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
(1) Clean the #1 connecting rod bearing and the #1 pin of crankshaft, and apply engine oil to the #1 pin
of crankshaft.
(2) Set the #1 connecting rod bearing to the #1 connecting rod and #1 connecting rod cap.
(3) Set the #1 connecting rod, #1 connecting rod cap and #1 connecting rod cap bolt to the #1 pin of
crankshaft.
NOTE:
Each connecting rod has its own mating cap. Make sure that they are assembled correctly by checking
their matching symbol.
Use a new connecting rod cap bolt.
Apply a coat of engine oil to the #1 connecting rod cap bolt thread.
(A) Thickness gauge (B) Connecting rod
ME-06142
(A)
(B)
(B)
(A)
15WRX_STI_US_EN.book 325 ージ 20  
ME(w/o STI)-326
Cylinder Block
MECHANICAL
(4) Using ST, tighten the #1 connecting rod cap bolts to 10 N·m (1.0 kgf-m, 7.4 ft-lb) in numerical order
as shown in the figure, then retighten the bolts to 25 N·m (2.5 kgf-m, 18.4 ft-lb) in numerical order as
shown in the figure.
CAUTION:
Make sure to hold the crankshaft securely during work.
When holding the crankshaft, be careful not to damage the crankshaft.
ST 18270AA020 SOCKET
(5) Using ST and angle gauge, tighten the #1 connecting rod cap bolts with specified angle in numerical
order as shown in the figure.
CAUTION:
Make sure to hold the crankshaft securely during work.
When holding the crankshaft, be careful not to damage the crankshaft.
NOTE:
Prevent angle gauge from rotating using a V-block, etc.
ST 18270AA020 SOCKET
Tightening angle:
90°
+5°
–0°
ME-06870
(1)
(2)
ST
ME-07270
(1)
(2)
ST
15WRX_STI_US_EN.book 326 ージ 20  
ME(w/o STI)-327
Cylinder Block
MECHANICAL
(6) In the same manner, install the #2, #3 and #4 connecting rods.
(7) Check the thrust clearance of each connecting rod using a thickness gauge. If it is not within the stan-
dard, replace the connecting rod.
NOTE:
Measure the thrust clearance of each connecting rod at several points, and replace the connecting rod if
there is uneven wear.
Connecting rod thrust clearance:
Standard
0.070 — 0.330 mm (0.0028 — 0.0130 in)
5) Check the oil clearance on each connecting rod bearing using plastigauge.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
(1) Clean the #1 connecting rod bearing and the #1 pin of crankshaft.
(2) Set the #1 connecting rod bearing to the #1 connecting rod and #1 connecting rod cap.
(3) Place a plastigauge across the #1 pin of crankshaft, and set the #1 connecting rod, #1 connecting rod
cap and #1 connecting rod cap bolt to the #1 pin of crankshaft.
NOTE:
Each connecting rod has its own mating cap. Make sure that they are assembled correctly by checking
their matching symbol.
Use a new connecting rod cap bolt.
Apply a coat of engine oil to the #1 connecting rod cap bolt thread.
ME-06872
15WRX_STI_US_EN.book 327 ージ 20  
ME(w/o STI)-328
Cylinder Block
MECHANICAL
(4) Using ST, tighten the #1 connecting rod cap bolts to 10 N·m (1.0 kgf-m, 7.4 ft-lb) in numerical order
as shown in the figure, then retighten the bolts to 25 N·m (2.5 kgf-m, 18.4 ft-lb) in numerical order as
shown in the figure.
CAUTION:
Make sure to hold the crankshaft securely during work.
When holding the crankshaft, be careful not to damage the crankshaft.
During tightening, be careful not to move the #1 connecting rod and the #1 connecting rod cap.
ST 18270AA020 SOCKET
ME-06870
(1)
(2)
ST
15WRX_STI_US_EN.book 328 ージ 20  
ME(w/o STI)-329
Cylinder Block
MECHANICAL
(5) Using ST and angle gauge, tighten the #1 connecting rod cap bolts with specified angle in numerical
order as shown in the figure.
CAUTION:
Make sure to hold the crankshaft securely during work.
When holding the crankshaft, be careful not to damage the crankshaft.
During tightening, be careful not to move the #1 connecting rod and the #1 connecting rod cap.
NOTE:
Prevent angle gauge from rotating using a V-block, etc.
ST 18270AA020 SOCKET
Tightening angle:
90°
+5°
–0°
ME-07270
(1)
(2)
ST
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MECHANICAL
(6) Using ST, loosen the #1 connecting rod cap bolt, and remove the #1 connecting rod cap bolt and #1
connecting rod cap.
CAUTION:
Make sure to hold the crankshaft securely during work.
When holding the crankshaft, be careful not to damage the crankshaft.
During removal, be careful not to move the #1 connecting rod and the #1 connecting rod cap.
ST 18270AA020 SOCKET
(7) Determine oil clearance of the #1 connecting rod bearing by matching the widest point of the plasti-
gauge on #1 pin of crankshaft against scale printed on a package of the plastigauge. If it is not within the
standard, replace the #1 connecting rod bearing.
NOTE:
Measure the outer diameter of crankshaft pin using micrometer, and select the suitable size connecting rod
bearing when replacing the connecting rod bearing.
Unit: mm (in)
Bearing
Connecting rod bearing thickness (at center) Crankshaft pin outer diameter
Standard Standard
Standard size
1.492 — 1.508
(0.0587 — 0.0594)
49.976 — 50.000
(1.9676 — 1.9685)
0.03 (0.0012)
Undersize
1.511 — 1.515
(0.0595 — 0.0596)
49.946 — 49.970
(1.9664 — 1.9673)
0.05 (0.0020)
Undersize
1.521 — 1.525
(0.0599 — 0.0600)
49.926 — 49.950
(1.9656 — 1.9665)
0.25 (0.0098)
Undersize
1.621 — 1.625
(0.0638 — 0.0640)
49.726 — 49.750
(1.9577 — 1.9587)
ME-06873
ST
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MECHANICAL
Connecting rod bearing oil clearance:
Standard
0.025 — 0.055 mm (0.0010 — 0.0022 in)
(8) Completely remove the plastigauge.
(9) In the same manner, check oil clearance of the #2, #3 and #4 connecting rod bearings.
5. PISTON PIN & CONNECTING ROD BUSHING
1) Check that the connecting rod bushing is not damaged.
2) Check the clearance between piston pin and connecting rod bushing. Check the clearance between piston
pin and connecting rod bushing by measuring the outer diameter of piston pin and the inner diameter of con-
necting rod bushing respectively.
(1) Measure the outer diameter of piston pin with a micrometer.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Measure the outer diameter of the piston pin at the two locations as shown in the figure, and read the value
of most worn location.
Record the measured value.
ME-06108
ME-06106
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MECHANICAL
(2) Using a caliper gauge, measure the inner diameter of connecting rod bushing.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Measure the inner diameter of the connecting rod bushing at the two locations as shown in the figure, and
read the value of most worn location.
Record the measured value.
(3) Calculate the clearance between piston pin and connecting rod bushing.
Clearance between piston pin and connecting rod bushing:
Standard
0.004 — 0.026 mm (0.0002 — 0.0010 in)
3) If the clearance between piston pin and connecting rod bushing is not within the standard, replace the con-
necting rod and piston pin as a set.
ME-06874
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MECHANICAL
6. CRANKSHAFT AND CRANKSHAFT BEARING
1) Clean the crankshaft completely, and check it for cracks using liquid penetrant tester.
2) Using a dial gauge, check the crankshaft bend. If it exceeds the limit, grind to correct the crankshaft journal
or replace the crankshaft.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
If a suitable V-block is not available, using just the #1 and #5 crankshaft bearings on cylinder block, posi-
tion the crankshaft on cylinder block. Then, measure the crankshaft bend using a dial gauge.
When grinding to correct the crankshaft journal, refer to step 3).
Crankshaft bend:
Limit
0.035 mm (0.0014 in)
3) Using a micrometer, check the outer diameter of crankshaft pin, outer diameter of journal, cylindricality,
and out-of-roundness. If it is not within the standard, replace the connecting rod bearing or crankshaft bear-
ing, and grind to correct the crankshaft pin or journal or replace the crankshaft as required.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Select the suitable size connecting rod bearing or crankshaft bearing when replacing the connecting rod
bearing or crankshaft bearing.
When grinding to correct the crankshaft pin or journal, finish them to the suitable outer diameter as shown
in the table below according to the undersize bearing to be used.
Unit: mm (in)
Bearing
Connecting rod
bearing thickness
(at center)
Crankshaft pin outer
diameter
Crankshaft bearing thickness (at center)
Crankshaft journal
outer diameter
#1, #2, #3, #4 #5
Standard Standard Standard Standard Standard
Standard size
1.492 — 1.508
(0.0587 — 0.0594)
49.976 — 50.000
(1.9676 — 1.9685)
2.495 — 2.513
(0.0982 — 0.0989)
2.493 — 2.511
(0.0981 — 0.0989)
67.985 — 68.009
(2.6766 — 2.6775)
0.03 (0.0012)
Undersize
1.511 — 1.515
(0.0595 — 0.0596)
49.946 — 49.970
(1.9664 — 1.9673)
2.519 — 2.522
(0.0992 — 0.0993)
2.517 — 2.520
(0.0991 — 0.0992)
67.955 — 67.979
(2.6754 — 2.6763)
0.05 (0.0020)
Undersize
1.521 — 1.525
(0.0599 — 0.0600)
49.926 — 49.950
(1.9656 — 1.9665)
2.529 — 2.532
(0.0996 — 0.0997)
2.527 — 2.530
(0.0995 — 0.0996)
67.935 — 67.959
(2.6746 — 2.6755)
0.25 (0.0098)
Undersize
1.621 — 1.625
(0.0638 — 0.0640)
49.726 — 49.750
(1.9577 — 1.9587)
2.629 — 2.632
(0.1035 — 0.1036)
2.627 — 2.630
(0.1034 — 0.1035)
67.735 — 67.759
(2.6667 — 2.6677)
ME-06875
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MECHANICAL
Crankshaft pin:
Cylindricality
Limit
0.006 mm (0.0002 in)
Out-of-roundness
Limit
0.005 mm (0.0002 in)
Grinding limit (dia.)
To 49.726 mm (1.9577 in)
Crankshaft journal:
Cylindricality
Limit
0.006 mm (0.0002 in)
Out-of-roundness
Limit
0.005 mm (0.0002 in)
Grinding limit (dia.)
To 67.735 mm (2.6667 in)
4) Inspect the crankshaft bearing for scar, peeling, seizure, melting or wear, etc.
ME-05379
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Cylinder Block
MECHANICAL
5) Use a thickness gauge to check the thrust clearance of crankshaft at thrust of #5 crankshaft bearing. If it
is not within the standard, replace the #5 crankshaft bearing.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
Set all the crankshaft bearings onto the cylinder block, then mount the crankshaft on the cylinder block,
and use a thickness gauge to measure the thrust clearance of crankshaft.
Select the #5 crankshaft bearing of suitable size by referring to step 3) when replacing #5 crankshaft bear-
ing.
Crankshaft thrust clearance:
Standard
0.130 — 0.308 mm (0.00512 — 0.01213 in)
6) Check the oil clearance on each crankshaft bearing using plastigauge.
NOTE:
Measurement should be performed at a temperature of 20°C (68°F).
(1) Install the cylinder block LH to the engine stand.
CAUTION:
When the engine stand is not used, place a wood board wrapped with a waste cloth to prevent the
knock pin damage and to stabilize the cylinder block before work.
Be careful not to scratch the mating surface of cylinder block during work.
(2) Remove the liquid gasket from cylinder block.
(3) Clean each crankshaft bearing and crankshaft journal.
ME-06876
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MECHANICAL
(4) Set each crankshaft bearing to the cylinder block.
CAUTION:
When performing the operation of the cylinder block RH, be careful of the following.
1. Place a wood board wrapped with a waste cloth to prevent the knock pin damage and to stabilize
the cylinder block before work.
2. Be careful not to scratch the mating surface of cylinder block during work.
(5) Set the crankshaft to the cylinder block LH.
ME-06819
LH
RH
ME-06820
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MECHANICAL
(6) Place a plastigauge across the crankshaft journals and set the cylinder block RH to the cylinder block
LH.
(7) Apply a coat of engine oil to the washers and cylinder block mounting bolt threads.
NOTE:
To prevent mixture of engine oil into the water jacket, do not apply a large amount.
(8) Tighten all mounting bolts with a torque of 35 N·m (3.6 kgf-m, 25.8 ft-lb) in numerical order as shown
in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06822
(8)
(4)
(3)
(9)
(6)
(2)
(5)
(7)
(1)
(10)
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MECHANICAL
(9) Loosen all mounting bolts by 180° in numerical order as shown in the figure.
CAUTION:
When loosening the mounting bolts, hold the cylinder block LH while not holding the cylinder block
RH to ensure the joint accuracy of the cylinder block.
ME-06816
(3)
(7)
(8)
(10)
(2)
(5)
(9)
(6)
(4)
(1)
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Cylinder Block
MECHANICAL
(10) Tighten all mounting bolts with a torque of 35 N·m (3.6 kgf-m, 25.8 ft-lb) in numerical order as shown
in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06822
(8)
(4)
(3)
(9)
(6)
(2)
(5)
(7)
(1)
(10)
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Cylinder Block
MECHANICAL
(11) Loosen the mounting bolts (4 places) by 180° in numerical order as shown in the figure.
CAUTION:
When loosening the mounting bolts, hold the cylinder block LH while not holding the cylinder block
RH to ensure the joint accuracy of the cylinder block.
ME-06824
(3)
(4)
(1)
(2)
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MECHANICAL
(12) Tighten the mounting bolts (4 places) with a torque of 17 N·m (1.7 kgf-m, 12.5 ft-lb) in numerical or-
der as shown in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06825
(2)
(1)
(4)
(3)
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MECHANICAL
(13) Using angle gauge, tighten the mounting bolts (4 places) with specified angle in numerical order as
shown in the figure.
CAUTION:
When tightening the mounting bolts with specified angle, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
Tightening angle:
60°
±
ME-07266
(1)
(2)
(4)
(3)
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MECHANICAL
(14) Loosen the mounting bolts (6 places) by 180° in numerical order as shown in the figure.
CAUTION:
When loosening the mounting bolts, hold the cylinder block LH while not holding the cylinder block
RH to ensure the joint accuracy of the cylinder block.
ME-06827
(1)
(4)
(5)
(2)
(3)
(6)
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MECHANICAL
(15) Tighten the mounting bolts (6 places) with a torque of 17 N·m (1.7 kgf-m, 12.5 ft-lb) in numerical or-
der as shown in the figure.
CAUTION:
When tightening the mounting bolts with specified torque, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
ME-06828
(6)
(3)
(2)
(5)
(4)
(1)
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Cylinder Block
MECHANICAL
(16) Using angle gauge, tighten the mounting bolts (6 places) with specified angle in numerical order as
shown in the figure.
CAUTION:
When tightening the mounting bolts with specified angle, hold the cylinder block LH while not hold-
ing the cylinder block RH to ensure the joint accuracy of the cylinder block.
Tightening angle:
60°
±
ME-07267
(1)
(4)
(6)
(5)
(2)
(3)
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MECHANICAL
(17) Loosen the cylinder block mounting bolts in numerical order as shown in the figure, and separate the
cylinder block RH and LH.
NOTE:
Lift the cylinder block RH slightly, and confirm that the crankshaft is remaining in the cylinder block LH. If the
cylinder block RH is lifted carelessly when separating, the crankshaft may stick to cylinder block RH, then fall
off.
ME-06816
(3)
(7)
(8)
(10)
(2)
(5)
(9)
(6)
(4)
(1)
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MECHANICAL
(18) Determine the crankshaft oil clearance by matching the widest point of the plastigauge on each jour-
nal against scale printed on a package of the plastigauge. If it is not within the standard, replace the
crankshaft bearing, and grind to correct the crankshaft journal or replace the crankshaft as required.
NOTE:
Select the crankshaft bearing of suitable size by referring to step 3) when replacing crankshaft bearing.
When grinding to correct the crankshaft journal, finish it to the suitable outer diameter by referring to step
3) according to the undersize bearing to be used.
Crankshaft oil clearance:
Standard
0.013 — 0.031 mm (0.00051 — 0.00122 in)
(19) Completely remove the plastigauge.
ME-06108
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